<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<title>Insert title here</title>
		<style type="text/css">
.selected {
	background-color: #f00;
}

.unselected {
	background-color: #fff;
}
</style>
		<script type="text/javascript">

function f() {

	document.getElementById("mail").className = null;
}
function f1() {

	document.getElementById("mail").className = "selected";
}
</script>
	</head>
	<div id="mail" index="5">
		ggg
	</div>
	<button onclick="f()">
		测试
	</button>
	<button onclick="f1()">
		测试
	</button>
	<body>
	</body>
</html>

